1. Field of the Invention
The present invention relates to a casing cover for use in separating a motor assembly and a pump assembly from each other in a pump device such as a circulating pump for handling fresh water, and a pump device having such a casing cover.
2. Description of the Related Art
Pump devices such as a circulating pump for handling fresh water are required to prevent the liquid that is being handled under an increased pressure in a pump casing from leaking out of a high-pressure opening in the pump casing into a motor assembly. To meet such a requirement, it has widely been customary to separate a motor assembly and a pump assembly from each other with a casing cover with a mechanical seal mounted therein for sealing a main shaft and also to seal the pump casing in a water-tight fashion with an O-ring, for example.
FIG. 1 of the accompanying drawings shows, in enlarged fragmentary cross section, a fixed region of a casing cover in a conventional general pump device, the casing cover being formed by pressing a stainless steel plate, for example. The casing cover, generally denoted by 10, has a flat panel portion 12, a cylindrical wall portion 14, and a flange portion 16 which are integrally formed by pressing a flat plate. The cylindrical wall portion 14 has an inner circumferential surface serving as a motor-side faucet-joint surface (motor-side positioning portion) 14a held against a motor bracket 20 and an outer circumferential surface serving as a pump-side faucet-joint surface (pump-side positioning portion) 14b held against a pump casing 22. The motor-side faucet-joint surface 14a, i.e. the motor-side register fit surface 14a, is fitted over the motor bracket 20, and the pump-side faucet-joint surface 14b, i.e. the pump-side register fit surface 14b, is fitted in the pump casing 22, providing a faucet-joint structure, i.e. a socket-and-spigot joint (positioning) structure.
Since the inner and outer circumferential surfaces of the cylindrical wall portion 14 are fitted over and in the motor bracket 20 and the pump casing 22, when the flat plate is pressed to form the cylindrical wall portion 14, one of the inner and outer circumferential surfaces of the cylindrical wall portion 14, e.g., the inner circumferential surface, is used as a dimensional reference to achieve desired dimensional accuracy.
However, in the conventional casing cover 10, when the flat plate is pressed to form the cylindrical wall portion 14, one of the inner and outer circumferential surfaces of the cylindrical wall portion 14, e.g., the inner circumferential surface, is used as a dimensional reference, since the flat plate generally suffers thickness variations, it is difficult to achieve desired dimensional accuracy for the other of the inner and outer circumferential surfaces of the cylindrical wall 14, e.g., the outer circumferential surface. Furthermore, when the pump device is serviced for maintenance, e.g., when the mechanical seal is replaced, because the casing cover 10 tends to stick to the motor bracket 20 and the pump casing 22 due to rust or the like, it is difficult to remove the casing cover 10 while both the inner and outer circumferential surfaces of the cylindrical wall portion 14 are being of normal dimensions.
It is therefore an object of the present invention to provide a casing cover which is capable of fitting with members of both a motor assembly and a pump assembly highly accurately in providing a faucet-joint (positioning) structure, and of disassembling and removing a member thereof held in interfitting faucet-joint (positioning) engagement with the members of the motor assembly and the pump assembly while keeping normal dimensions, and a pump device having such a casing cover.
According to the present invention, there is provided a casing cover for use in separating a motor assembly and a pump assembly from each other in a pump device, comprising: a cylindrical wall portion having a step, a motor-side positioning portion positioned on one side of the step for being fitted to a member of the motor assembly, and a pump-side positioning portion positioned on the other side of the step for being fitted to a member of the pump assembly.
Since the motor-side positioning portion and the pump-side positioning portion are individually positioned one on each side of the step of the cylindrical wall portion, the casing cover can be formed by pressing a flat plate using both the motor-side positioning portion and the pump-side positioning portion as dimensional references, both the motor-side positioning portion and the pump-side positioning portion can be formed to shape with high dimensional accuracy. The casing cover with such high dimensional accuracy can be assembled easily and quickly in the pump device, and can be disassembled and removed while the motor-side positioning portion and the pump-side positioning portion are being dimensionally maintained.
The motor-side positioning portion may comprise a motor-side faucet-joint surface, and the pump-side positioning portion may comprise a pump-side faucet-joint surface, thereby providing a faucet-joint structure.
The motor-side faucet-joint surface may be disposed on one of an inner and outer circumferential surface of the cylindrical wall portion, and the pump-side faucet-joint surface may be disposed on the other of the inner and outer circumferential surface of the cylindrical wall portion.
According to the present invention, there is also provided a pump device comprising: a motor assembly; a pump assembly; and a casing cover separating the motor assembly and the pump assembly from each other; the casing cover comprising a cylindrical wall portion having a step, a motor-side positioning portion positioned on one side of said step for being fitted to a member of the motor assembly, and a pump-side positioning portion positioned on the other side of said step for being fitted to a member of the pump assembly.
The above and other objects, features, and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate a preferred embodiment of the present invention by way of example.